Batteries, in particular lithium-ion batteries, are rechargeable electrical energy stores the use of which, for example in mobile telephones, laptop computers, portable consumer goods and hybrid or electric vehicles, is very widespread. Owing to an observed trend in recent years, it is to be expected that new batteries or battery systems, on which constantly increasing demands are placed, will increasingly be used in future. In addition to a high degree of safety and reliability which needs to be ensured, ever-increasing demands also arise owing to the ever-decreasing available installation space in the batteries or to the permissible weight of the batteries or battery systems. Furthermore, the batteries or battery systems must be efficient and cost-effective to produce.
Moreover, the use of so-called hard-case battery cells or of battery cells with hard-shell housings which have a prismatic or cylindrical housing is known from the prior art. Battery cells such as this can be, for example, lithium-ion battery cells, nickel-metal hydride battery cells, lithium metal-polymer battery cells or else other electrochemical energy stores which have an appropriate housing.
Individual battery cells, for example six or twelve lithium-ion battery cells, which are used in the automotive sector, are interconnected in series or in parallel to form a battery module. A plurality of battery modules are assembled to form a battery pack subunit and a plurality of battery pack subunits are in turn interconnected to form a battery pack. In order to meet the demand on the installation space mentioned above, the battery cells should be arranged as close to one another as possible.
FIG. 1 shows a battery module 50, a battery pack subunit 60 and a battery pack 70 from the prior art. In this example, the battery pack 50 comprises six battery cells 40 which are fixed by a belt or a steel strip. In FIG. 1, a total of eight such battery modules 50 are assembled to form a battery pack subunit 60, two of which battery pack subunits are in turn assembled in this example to form a battery pack 70. The battery cells 40 each have two battery cell terminals 11, 12, wherein the battery cell terminals 11, 12 of adjacent battery cells 40 within a battery module 50 are electrically conductively connected to one another.
What is increasingly challenging in the mechanical design of the battery modules is reducing the weight and achieving efficient construction and connection technology. In this case, the battery modules or the components thereof are increasingly important since they take up the largest part of the assembly time and account for the majority of the weight of the battery pack. For this reason, the greatest potential for saving weight and costs in the manufacture of a battery pack is in the standardization of the design of said battery pack. With such standardization, it is possible to achieve a streamlining effect which brings with it a decrease in costs.
One of the components of battery modules is their cover which is to be referred to henceforth as battery module cover. A battery module cover 30 from the prior art is shown in FIG. 1. This battery module cover 30 has rectangular cutouts 1 which are arranged parallel to the longer edges of the battery module cover 30. In this example of a battery module cover 30 from the prior art, the battery module cover 30 has in each case six rectangular cutouts 1 arranged along the longer sides of said battery module cover, wherein in each case two cutouts 1 lie opposite one another symmetrically to an imagined axis of symmetry which runs through the battery module cover 30 centrally and parallel to the longer sides or edges of the battery module cover 30. The battery cell terminals 11, 12 of six battery cells in total can be guided through said cutouts 1. In this example, battery cell connectors 8 with openings which correspond to the cutouts 1 are screwed on the battery module cover 30. If a battery module 50 as illustrated in FIG. 1 is connected to the battery module cover 30 illustrated in FIG. 2, the battery cells 40, of which there are six in this example, of the battery module 50 are connected in series via the battery cell connectors 8 of the battery module cover 30. Furthermore, the battery module cover 30 illustrated in FIG. 2 has cables 7 which are electrically connectable to the battery cell terminals 11, 12 of the battery cells 40 and are connectable to a sensor and via which, for example, measurements for determining the state of charge, the temperature or the no-load voltage of all of the battery cells 40 or of individual battery cells 40 can be performed or other data which is necessary for monitoring all of the battery cells 40 or individual battery cells 40 can be transmitted.
In addition, a battery module which has a battery module cover for protecting the battery module and via which the battery module can additionally be fixed in a motor vehicle is known from JP 2009-164085 A.